The purpose of the method in accordance with the invention is the manufacture of individual packets for a product, the product being in any form able to be packed into sachets (liquid, semi-liquid, paste, powder, granular, etc.). Such packaging is currently used in extremely varied fields, such as cosmetics, pharmaceuticals, food-processing, etc.
In order to manufacture such packaging, many methods implementing the hermetic assembly of one or several film or films are known, whereby a dose of the product being packed is imprisoned. For example, a method that implements the following steps is already known: the unwinding of a lower film, the depositing on the latter of individual doses of the product needing to be packed, the placing of a second film on top of the first, then the sealing of the two films around each individual dose and the cutting-out of each dose.
The known methods have the inconvenience of restricting the manufacturing rate embodied due to the implementation mode of one or several of the aforementioned steps. The first factor restricting the embodiment speed is the depositing of the individual doses on the lower film: this step requires the use of means to deposit the product, necessitating very precise dimensions, volume and contour, and which are not compatible with very high speeds. In all events, such a sequential or intermittent dosage is intrinsically not as fast as a continuous dosage.
In other cases, the restricting factor is constituted by the sealing implementation mode. Hence, two possibilities can be distinguished: either the sealing technique imposes stoppage at regular intervals of the film unwinding (notably between each dose) in order to enable sealing under good conditions, or the technique used enables the continuous unwinding of the films, but at a relatively low speed in order to have time to implement adequate sealing.
A method is also known that enables to manufacture individual packets, or unidoses, of tubular shape, commonly called “sticks”. This method is currently mainly implemented in the food-processing industry (for example, for individual sachets of sugar, soluble coffee, etc.). The method for manufacturing sticks implements the following steps:                a reel of thermosealing plastic film is unwound, then cut into longitudinal strips by the rotary blades, the width of each strip determining the final width of the sticks;        once cut into length, the film arrives on a shaping device which joins the edges flesh-to-flesh, then embodies a longitudinal seal;        each stick thus formed is drawn towards the bottom by the horizontal sealing clamps, which embody a transversal seal;        the stick is filled up and the top opening is closed by a transversal seal;        
The speeds achievable using such a method are limited by the actual nature of said method. Indeed, all machines implementing such a method undergo the constraint of having to operate so-called “vertical and intermittent” filling. Hence, not only the filling (or dosage) and sealing operations are not performed continuously, i.e. via uninterrupted unwinding, but, moreover, such operations can, in no event, be simultaneous. Another inconvenience, the kinematics implemented by this type of machine is both complex and costly, and also contributes to restricting the manufacturing speeds.